import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebFilter(filterName="LoginFilter")
public class LoginFilter implements Filter {
    public void destroy() {
    }

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {
        if(((HttpServletRequest) req).getRequestURI().contains("token" ) && ((HttpServletRequest) req).getSession().getAttribute("username")==null)
            ((HttpServletResponse) resp).sendRedirect("https://cas.dgut.edu.cn?appid=javaee&state=STATE");

        chain.doFilter(req,resp);
    }

    public void init(FilterConfig config) throws ServletException {

    }

}
